Cutter



H..M. LOOMER.

CUTTER.

APPLICATION FILED 001.1. 1918.

1,412,084. Patented Apr. 11, 1922.

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' HENRY M. LOOMER, or BEVERLY, ivrAssAonusnrrs, Assre'non 'lO UNITED SHOE MACHINERY CORPORATION, or LPATERSON,

NEW JERSEY.

new JERSE A CORPORATION or;

CUTTER.

Specification of Letters Patent. Patgntgd Apr 11', 192-2.

Application filed October 7, 1918. Serial No. 257,203.

T 0 all 'whom-c't-may concern:

Be it known that I, HENRY M. LooMnn, a citizen f the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain Improvements in Cutters, of which the following description, in connection with the accompanying drawings, is a specification, like reference characters on the drawings indicating'like parts in the several figures.

This invention relates to cutters and is illustrated by, way of example as embodied in heel trimming cutters especially designed for use in heel trimming machines, although the invention is not limited to such use.

The cutters used in heel trimming machines Of certain types are'clamped edgewise in cutter heads carried by the machines. Such cutters are. elongated plates of steel sharpened at one end andthey are ground back on that end as they become dull. They are in many cases ground back so far by repeated sharpening that not enoughlength remains to give'the clamping mechanism a firm gripon them, with the result that the cutters sometimes .fly out of. the heads and seriously injure the operators The likelihood of flying out is greatly increased by the fact that such cutters rotate at high speed, for example, 7000 R. P. M.

It is a principal object of my invention to provide a cutter with means adapted to guard against use when the cutter has been ground to a predetermined limit of safety. An important feature of the invention consists in a cutter marked to indicate the safe limit of grinding. In the illustrated embodiment the cutter is formed in such manand will then be defined in the accompany- In the drawings, 7 I V Fig. 1 is a perspective of. a cutter embodying my invention;

Fig. 2 is a view of the under side of the cutter, and

Fig. 3 shows the cutter in the heel trim ming machine.

expense. 'in making the cutters so short that not" The machine has a shaft 10 adapted for.

rapidrotation, and carrying a'cutter head plate 12. Thisplate has two ribs H and 1.6, circular-arcuate in form, with their i centers lying beyond the center of the shaft 10, in each case. The cutters18 are curved andhave notches 20 in their edges adapted to fit over the ribs 14, 16 and'simil'ar jribs on a second clamping plate not shown, hetweenv which and the plate 12 they are securely clamped. abutment, plate 22 is mounted in the head to position the cutters by contact with their rear ends 2 l. As the cutting edges 26 become dull the cutters are ground back and the abutment plate is cutters forward on the ribs 1 k, 16 in order to keep the cutting edges 26 at the same-- The mechanism so This practice results sometimes turned forward, thus gradually moving the enough of them is left to give the clamping Z plates a firm bearing on them. Such a cut-3 ter sometimes flies out of the machine, subjecting everyone in the vicinity tothe liability of serious injury. I have avoided this objectionby marking the cutter to indicate the safe limit of grinding. In the cutter shown, the mark mutilates the cutter so as to destroy any cutting edge passing through the point of mutilation. This is accom plished very simply in the cutter shown by making two holes 28, extending into the body of the cutter through one Ofthe faces 1 .that form the cutting edge. .Vhenthe cutter is ground back to the location of the holes, if the-operator neglects the warning that the safe limit, of grinding has been reached, the cutting edge will be destroyed by the mutilation, and he would have to grindclear through the holes (about inch in the cutter shown) before he could get a complete operative cutting edge. This wastes so much time that he will secure new cutters inpreference. The holes 28' areso located that enough of the cutter 30 remains behind them to give the clamping plates a firm grip, thus avoiding the danger of a cutter flying out and injuringsomeone.

Having described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1.-ln combination, a cutting blade and a holder therefor comprising clamping means constructed to clamp the blade edgewise throughout its length, said blade having a localized irregular formation so located as to leave the cutting edge initially intact but to render the cutting edge unfit for its intended use when it has been ground back so far as to deprive the blade of a safe clamping length. a

2 A cutting blade for trimming Ina-chines, having a cutting edge, clamp-engaging faces extending from opposite ends of said cutting edge to the rear end of the blade, and a localized irregular formation between said clamp-engaging faces and placed so as to leave said cutting edge intact until, by grinding back the blade to sharpen said edge, said clamp-engaging faces are deprived of adequate clamping length.

3. A cutting blade having a cutting edge and clamp-engaging faces extending from opposite ends of said cutting edge to the rear end of the blade, all the marginal portions of the blade being integral but the blade having a mutilation surrounded by said marginal portions and located so as to destroy the cutting edge for its intended purpose when said edge has been ground back so far as to impair the safety of the blade.

4. A cutting blade having an integral principal face and anon-integral principal face the integrity of Which is impaired by a depression Wholly Within the margins of the blade, the first said face being beveled so as to form a cutting edge at the other said face, said depression being arranged to destroy said cutting edge for its intended purpose when said edge has been ground back to a line intersecting the depression.

In testimony whereof I have signed my name to this specification.

HENRY M. LOOMER. 

